These mixer valves usually have a cartridge-type body with a base and a lid and incorporate a mixer unit made up from two overlapping ceramic plates. One plate is fixed to the base of the body. The other plate is controlled from the outside and is movable on and with respect to the fixed one. The fixed plate has two water inlet holes which connect with two conduits for the separate supplying of hot and cold water and one hole for the outlet of water towards the delivery mouth of the tap to which the valve is fitted. As far as the mobile plate is concerned it is movable through a control lever and has a mixing chamber which selectively joins one or both the water inlet holes with the outlet one.
It has already been proposed that the mixer valves are to be fitted with a pressure balancer on a side having the water inlet holes of the fixed plate. The pressure balancer having a known structure which is suitable for compensating the variations of the pressure of water coming from a distribution network and which prevents the flow from surging, therefore keeping the ratio of the capacity of the two types of water constant.
At present the application of such a balancer requires the availability and the inserting of a suitable casing which is to connect to the body of the valve and which is designed to hold the balancer.